Apparatus for making a multielement electron gun member



Se t. 29, 1 970 SHINICHI SAWAGATA 3,530,560

APPARATUS FOR MAKING A MULTIELEMENT ELECTRON GUN MEMBER Filed Sept. 9, 1968 5 Sheets-Sheet 1 WIN/c!!! 541M619 7-4 I N VENTOR.

Sept. 29, 1970 SHINICHI SAWAGATA 3,530,560

APPARATUS FOR MAKING A MULTIELEMENT ELECTRON GUN MEMBER Filed Sept. 9, 1968 5 Sheets-Sheet 2 Sept 29, 1970 SHINICHI SAWAGATA 3,530,560

APPARATUS FOR MAKING A MULTIELEMENT ELECTRON GUN MEMBER Filed Sept. 9; 1968 s Sheets-Sheet s 303132 FIG. 4

'22 1 28 32 R F iv i v SHlNlCHI SAWAGATA APPARATUS FOR MAKING A MULTIELEMENT ELECTRON GUN Sept. 29, 1970 MEMBER 5 Sheets-Sheet 4 Filed Sept. 9, 1968 Sept. 29, 1970- SHINICHI SAWAGATA 3,530,560

, APPARATUS FOR MAKING A MULTIELEMENT ELECTRON GUN MEMBER Filed. Sept. 9, 1968 5 Sheets-Sheet 5 United States Patent US. Cl. 29-25.19 7 Claims ABSTRACT OF THE DISCLOSURE An apparatus for manufacturing an excellent triple electron gun member for use in a colour television set from electron gun units, comprising a truncated conical gauge having a plurality of grooves having V-shaped cross section and extending along the peripheral surface of said gauge at equal spaces from one another, a plurality of central rods each having a tapered lower portion to be inserted in said groove and an upper portion for carrying the electron gun unit and means for restricting the lateral and longitudinal movements of the rods. The inclination angle required for the gun units is determined by the taper angle of the central rod and the taper angle of the side surface of the gauge.

The present invention relates to an apparatus for as sembling a multielement electron gun member, particularly a triple electron gun member mostly adapted for use in a shadow mask type colour television picture tube.

This type of triple electron gun member is an assembly of three electron gun units spatially positioned at a prescribed inclination. The relative positions of these electron gun units are determined in such a manner that electron beams emitted from the three electron gun units intersect each other exactly at a single point on the shadow mask formed in a television tube. Without an exact intersection of the electron beams on the shadow mask, there would occur serious difficulties in the focus quality and colour matching to be achieve-d on the pickup surface of a colour television tube. For this purpose, it is required that the relative positions of the electron gun units be determined with considerable precision and that the electron gun member be assembled with such positions rigidly maintained.

Hitherto there have been proposed a variety of apparatus for assembling the aforementioned electron gun member. To date, however, it has been impossible to obtain an assembling device fully meeting the above described requests. To give a typical example of the prior art device, there has been used, for example, a type involving a locating member. This locating member consists of an inverted truncated conical body on the circumferential surface of which are formed three grooves at a prescribed interval along the longitudinal axis of the conical body. That is, the axes of the grooves are respectively inclined to that of truncated conical body at a prescribed angle in such a manner that the axes of the grooves intersect each other exactly at a single point below the bottom of the inverted truncated conical body. With such assembling device, the electron gun units are first kept in the aforesaid relative positions by being inserted into the grooves and securely held in the grooves by being pressed from the outside by a supporting means. Thereafter the electron gun units are integrally bonded together by, for example, insulating glass material to form an electron gun member with the relative positions of the electron gun units maintained as originally determined.

However, the aforementioned assembling device had the drawbacks that when the completed electron gun member was removed from the truncated conical body, the assembly was unavoidably subject to a more or less deformation, so that the relative positions of the electron gun units elaborately determined by the grooves were dislocated with the resultant failure to exhibit and extremely accurate image.

An object of the invention is to provide an apparatus having a plurality of central rods having a tapered lower part and a gauge shaped in a truncated cone so as to be capable of readily removing a completed electron gun member therefrom without any resultant undesirable external force.

In an aspect of the invention, an apparatus comprises a truncated conical gauge having a plurality of grooves of V-shaped cross section extending along the inclined surface of said gauge, central rods corresponding in numher to the number of said electron gun units having a downwardly tapered lower part to be inserted in the groove of said gauge and an upper part for carrying the electron gun unit, means to hold the lateral movement of said central rod by urging said tapered lower part of the central rod against said V-shaped groove, and second means movable with respect to the aforesaid means for holding said central rod endwise so as to restrict the longitudinal movement of said rod, these respective parts of said apparatus being of such arrangement that angle 0 of the axis of said electron gun unit with respect to said gun member is equal to the difference between an angle 0 of taper of said central rod and an angle 6 defined by the inclined surface of said truncated conical gauge and the axis of said gauge.

In the drawings:

FIG. 1 is a sectional view of an example of a triple electron gun member assembled by the apparatus of the present invention;

FIG. 2 is a sectional view of the electron gun member of FIG. 1 taken on line 22 of FIG. 1;

FIG. 3 is a section of an embodiment of the apparatus according to the invention;

FIG. 4 is a sectional view of the apparatus as shown in FIG. 3 taken on line 44 of FIG. 3;

FIG. 5 is a perspective view of the main part of the apparatus showing in FIGS. 3 and 4;

FIG. 6 is an enlarged front view of a central rod of the apparatus of FIGS. 3 to 5;

FIG. 7 is an enlarged elevation of the electron gun units mounted on a conical gauge of the apparatus according to the invention;

FIG. 8 is an enlarged perspective view of the conical gauge each of which groove supports the lower part of the central rod; and

FIG. 9 is a schematic cross sectional view of the tapered part of the central rod and the gauge illustrating angular relation therebetween.

Referring now to FIGS. 1 and 2, a triple electron gun member 10 assembled by the apparatus of the present invention comprises three electron gun units 11. Each electron gun unit has first to fourth cylindrical grid electrodes 12, 13, 14 and 15 respectively formed with an aperture in the centre for transmitting electron beams and arranged concentrically along the central axis ss' of the electron gun unit. The apertures of the grid electrodes are so disposed as to fall on the central axis s-s', so as to cause electron beams to be emitted through each electron gun unit exactly along the axis s-s. The central axes ss' of the three electron gun units are respectively inclined a prescribed angle 0 to the central axis cc' of the electron gun member so as to converge exactly at a single point on the extension of the central axis. The relative positions of the electron gun units are determined in such a manner that their central axes pass the apices of an equilateral triangle wherein a point on the central axis of the electron gun member 10 constitutes the centroid thereof. And the central axes of the electron gun units are spaced from the central axis of the electron gun member at an equal distance R.

Support bands 16 are fused to the grid electrodes 12 to 15 in a manner partly to surround the outer circumferential surface of each of them. The electron gun units are securely held together by causing both ends of each support band to be fused to a support rod 17 made of insulating glass thereby to bridge the grid electrodes of the adjacent electron gun units. This arrangement enables the electron gun units to be kept in the prescribed positions as described above.

On the base of a jig body 20 there are provided at equal intervals three support arms 21 extending upwardly from the periphery thereof at intervals from one another. To the upper inner side of the support arms 21 is fitted a gauge 22 having a truncated conical shape. On the outer circumferential surface of the gauge 22 are perforated concentrically at equal intervals three grooves 23 having a V-shaped cross section forming an included angle of 70, each of which extends in the direction of the bus of the conical gauge. These V-shaped grooves 23 are respectively disposed between the support arms 21. Into these grooves are fitted the lower portions 24 of central rods 25 as shown in FIG. 6. The central rod 25 is formed with a tapered shape with two small circular notches at the lower part 24 in such a manner that the circumferential surface of the lower part is inclined at 6 to the central axis of the rod 25.

The angle 0 must be chosen such that it is greater than the angle 0 of the inclined circumferential surface of the conical gauge. When the central axes of these rods are respectively inserted in the grooves, these respectively define an angle ti -0 :0 with the central axis A-A of the jig body 20. The circumferential surface of the upper portion 26 of the central rod extending above two flanges 27 is shaped stepwise in a tapered fashion or telescopically in line with the shape and size of the interior space of the electron gun unit, namely, these rods are arranged in such a manner that the central axes of three electron gun units intersect each other at one point in their extension. To one side of the support arms are pivoted keep plates 28 in a manner to cause one end thereof respectively to be rotated in a horizontal plane around axles 29 and to the other side of the support arms are similarly pivoted levers 30 at one end so as to be rotated in a vertical plane on the plate 28. The plate 28 has a projection on the inner surface in such a manner that the top surface thereof is contacted with the lower part of the central rod 25 so as to support the rod between the top surface and the inner surface of said groove. The outer surface of the other end portion of the plate is tapered toward its lower corner. At the upper ends of the levers 30 are provided knobs 31.

In the spaces between said arms there are removably inserted lower portions of three holding devices 32. The holding device 32 comprises a pole member 33 with integral protrusions 34, 35 and 36. On the lower protrusion 34 is formed an upwardly projecting protuberance 37 having a pointed tip. This protuberance is adapted to be snugly engaged in a recess provided on the bottom of the above described central rod 25. The middle protrusion 25 has an arcuate cutting formed on its edge surface. The upper protrusion is formed with a bore extending vertically in which is inserted a movable rod 38, which can move vertically through this hole. The movable rod 38 has on its lower part a large diameter portion 39 on the bottom of which is formed a small hole. In this hole may be engaged a smaller diameter portion of said central rod 25. On the upper end of this movable rod 38 is provided two pins 41 extending on both sides thereof and at right angles with said protrusions. On the pins 41 slidably engages forked portions of a lever 42 pivoted on the top of the pole member by means of a pin 43. The lever 42 is in frictional engagement with a plate spring 44 on the bottom surface, whose one end is secured to the pole member, so that the rear end of lever 42 is always exerted by a force tending to turn the lever in the counterclockwise direction about pin 43.

A method of assembling a triple electron gun member from three electron gun units is now described.

Individual gun units are mounted on the upper portion of corresponding central rods 25, and these assemblies are mounted on respective support devices 32 in order to hold the longitudinal movement of individual electron gun units, by engaging the recess formed on the bottom of the central rod 25 on the protruberance 40 of the lowermost protrusion 34 of the device 32, moving the movable rod 38 in the direction of an arrow or by turning the lever 42 in the direction of an arrow [3 against the spring force of plate spring 44 as shown in FIG. 3, and retracting the raised movable rod until the recess formed on the bottom thereof engages the upper end of the central rod 25. At this time it is preferable to insert spacers 45 to 48 between successively interposed cylindrical electrodes of the electron gun units to keep relative positions of the electrodes.

Each support device 32 carrying the electron gun unit is then mounted on the jig body 20 in such a manner that the lower portion 24 of rod 25 engages groove 23 of gauge 22. A keep plate 28 is then turned upon the lower portion 24 so as to hold the lower portion 24 between the groove 23 and the projection of the keep plate 28. As the groove 23 has a V-shaped cross section, the lower part 24 makes two linear contacts with the groove, thus greatly promoting the stability. Lever plate 30 is then turned over the upper surface of the keep plate 28. As the keep plate 28 is formed with an inclined outer surface, the projection of keep plate 28 engages the lower portion 24 of central rod 25 progressively strongly as the lever plate is turned over this inclined surface, thus ultimately holding the lateral movement of the rod 25.

In the aforedescribed manner, three central rods 25 are respectively inserted in the corresponding V-shaped grooves in the gauge 22 and held in position at an angle 0 with the axis of jig body 20, that is, the axis of gauge 22. On these three electron gun units held together at predetermined relative positions are fused support bands 16 such that they partly surround the circumferential surface of each electrode of the electron gun unit. The ends of support bands are then fused to support rods 17 made of an insulating glass, thereby bridging individual electrodes of adjacent electron gun units.

When removing the triple electron gun member thus assembled from the apparatus according to the invention, each of three individual levers 42 is turned in the direc tion of an arrow on to move movable rod 38 in the direction of an arrow 5, and at substantially the same time individual spacers are removed from between electrodes. In this state, the central rods 25 in engagement with projections 37 on the lowermost protrusions 34 are pulled slightly upwardly and individual supporting devices are turned down. The electron gun member 10 is then taken out of gauge 22 together with central rods which are thereafter removed from the completed electron gun member.

According to the present invention, the angle 0 of each gun unit relative to the triple electron gun member may be obtained by the difference between angle 0 of taper formed in the lower portion of central rod 25 and angle 0 defined by the side surfaces of the truncated conical gauge. The removal of the completed electron gun member from the assembling apparatus, which has heretofore been diflicult to carry out, can be easily achieved without deformation of the electron gun member as the gauge for setting the inclination angle is in the form of an un reverted truncated cone, enabling the removal of the member from the top of the truncated cone. Also, with this configuration of the gauge, the wear of the central rod is minimized as the central rods come in contact with the groove surfaces only at the beginning of removing the rods from the grooves.

Also, V-shaped cross section of the groove of the gauge enables linear contact of the lower part of the central rod along the groove, which enhances precision in holding the rods at predetermined relative positions as compared to area contact attainable with grooves having an arcuate cross section.

What is claimed is:

1. An apparatus for assembling an electron gun member from a plurality of electron gun units comprising a truncated conical gauge having a plurality of grooves of V-shaped cross section extending along the inclined surface of said gauge, central rods corresponding in number to the number of said electron gun units having a downwardly tapered lower part to be inserted in the groove of said gauge and an upper part for carrying the electron gun unit, means to hold the lateral movement of said central rod by urging said tapered lower part of the central rod against said V-shaped groove, and second means movable with respect to the aforesaid means for holding said central rod endwise so as to restrict the longitudinal movement of said rod, these respective parts of said apparatus being of such arrangement that the angle of the axis of said electron gun unit with respect to said gun member is equal to the difference between an angle 6 of taper of said central rod and an angle 0 defined by the inclined surface of said truncated conical gauge and the axis of said gauge.

2. An assembling apparatus claimed in claim 1 in which the inclined angle of said V-shaped groove defines approximately a right angle.

3. An assembling apparatus claimed in claim 1 in which said means to hold the lateral movement of the central rod comprises a jig body, a plurality of arms spaced from one another and extending about said jig body, said arms carrying said gauge such that the grooves of said gauge coincide with the spaces between the arms respectively, individual plates pivotally attached to one end of each of said arms, said keep plate having a projection which is to engage the lower part of said central rod, and lever plates each pivoted to respective one of said arms for pushing the keep plates toward the grooves and maintaining the keep plates in the resultant condition.

4. An assembling apparatus claimed in claim 1 in which said means to hold the longitudinal movement of said central rod is a supporting device removable from said means to hold the lateral movement of said central rod.

5. An assembling apparatus claimed in claim 1 in which said supporting device comprises a pole member, protrusions extending respectively from the upper and lower ends of said pole member in the same direction, an engaging member provided on the upper surface of the lower protrusion for engagement with the lower end of the central rod, a movable rod provided in the upper protrusion and longitudinally movable relative to the pole member, means for urging said movable rod always downwardly while on the other hand moving upwardly the downwardly urged rod against the urging force, and a member provided on one end of said movable rod for engagedly holding the upper end of the downwardly urged central rod.

6. An assembling apparatus claimed in claim 5 in which said means for urging the central rod comprises a lever pivoted on the upper end of the pole member and having one end in slidable engagement with said movable rod, and a plate spring secured at one end to said pole member and in frictional engagement with said lever to impart forces to the lever.

7. An assembling apparatus claimed in claim 1 wherein said angle 0 is greater than said angle 0 References Cited UNITED STATES PATENTS 2,914,317 11/1959 Miller et al 29--25.19 XR 3,363,298 1/1968 Merchant et al. 29-25.16 XR 3,434,819 3/1969 Merchant et al. 2925.16 XR JOHN F. CAMPBELL, Primary Examiner R. B. LAZARUS, Assistant Examiner U.S. C1. X.R. 269-37, 43 

